photo orientation issue in iPad

[cfw]

I'm planning to display my vacation photos in iPad but some (not all) portrait photos are being displayed as landscape. Those portrait photos might have been rotated on my PC running Win 7. It is my understanding Win software ignores exif tags while iPad is relying on exif's orientation tag for display.
I hope ExifToolGui will help me to fix the value of orientation tag. Currently all portrait photos are being displayed correctly under ExifToolGui (left bottom) and the orientation tag has a value "Horizontal (normal)", but I could not find a way to change the value (and don't know what is the proper value).
Did I miss something here?

[BogdanH]

Hi,

When displaying preview image (bottom-left), ExifToolGUI always takes Exif:Orientation value into account -that is, images are automatically rotated (if needed) when shown.
If you say, that images in GUI are shown correct, and they all have Orientation value "Horizontal" (even some of them appear vertically), that means, that those images have allready been phisically rotated. Meaning: such images will/must always appear correctly on every device -there's no need to modify Orientation tag.
I don't have iPad, to check how images are displayed there.

Bogdan

[cfw]

The photos display on PC (Windows 7) are correct. However, after synced with iPad, some pictures have wrong orientation. I have no clue how iPad displays pictures. That was the reason I try to use ExifTool to fix the problem but don't know how/

[Phil Harvey]

The way to fix this so an image is displayed correctly by any software is to rotate the image according to the EXIF Orientation tag, then reset the EXIF Orientation to horizontal.  I do this myself using jpegtran to do the lossless rotation.

But I am confused because this is what Bogdan says should be done to these preview images.  Could you post one of the images which displays incorrectly on the iPad so we can take a look?

- Phil

Edit: Fixed typo

[BogdanH]

Hi,

Just an add (to avoid confusion, hopefully):
Windows Photo Viewer (WPV) in Windows 7 doesn't make use of orientation tag value. The consequence:
If orientations of images are correct, when you see them by using WPV, then that means, that vertical/portrait oriented images have allredy been rotated.
And if they have been "properly" rotated, then Exif:Orientation tag must have "Horizontal (normal)" value. I can confirm, that if rotated by WPV, then Orientation tag get that value.
Now, what would happen, if images are rotated by "some" tool, which forgets to "reset" Orientation tag? Exactly! On Windows (by using WPV), everything would be fine. But when viewed by "proper" viewer (which makes use of Orientation tag), images would have wrong orientation.

Bogdan